Bavarian S 2/5 (Vauclain)

In the class S 2/ 5 of the Royal Bavarian State Railroad two express steam locomotives of American origin were classified with Vauclain engine.

To get to know the then largely unknown in Germany Construction principles of American locomotives, imported Bavarian State Railways in 1899 and 1900 four locomotives of the manufacturer Baldwin. After the two 1899 delivered Consolidation freight locomotives with the wheel arrangement 1'D ( section E I) followed in 1900 two Atlantic - express locomotives ( wheel arrangement 2'B1 ). There were typical American locomotives, which the boiler and engine were identical to the locomotives of the class A-1 of the Milwaukee Road. Also, the wheelbase was almost the same for both types, but the driving wheels of the Bavarian locomotives with 1,829 mm diameter were smaller than those of the A-1 ( 1.981 mm), so that a lower by about a ton total weight was (at that time were in the USA standard axle loads are not much higher than in Europe).

The locomotives had a four-cylinder compound engine of the type Vauclain, in which each one high - and low-pressure cylinders were placed directly over each other and worked on a common drive rod. The advantage of this design was that no hard to reach inner engines with expensive goiter axes were necessary.

While this engine design could not prevail at the state railway and even in Europe, it was recognized in the American bar frame some advantages, including better accessibility to an internal engine. Therefore, this frame design was then applied also in the top ten in 1904, built by Maffei series locomotives of Class S 2/ 5 as well as all the later Bavarian four-cylinder compound locomotives, but notwithstanding received an engine with inside cylinders and goiter axis of the American locomotives.

The two Baldwin locomotives remained with the train numbers 2398 and 2399 until after the First World War in action. In preliminary renumbering plan of the Deutsche Reichsbahn in the early 1920s were the two locomotives still than 14 131 and 14 132 included, but a little later they were already retired. It is worth noting in this context that the American models - after a conversion to a two-cylinder steam engine - until the end of the 1930s were in use.